The great drought of 2009 is largely over. How bad was it?

The short answer is that, statewide, it was relatively mild. But for certain localized areas this spring and summer’s drought was the second most severe drought in the state’s history.

Let’s begin with a review of drought conditions nearly three months ago, on August 4. You remember, summer, don’t you? Very hot this year. Record-setting, in fact, for the Houston area. And it was also dry. Anyway, here’s the August 4 map:

U.S. Drought Monitor

At the time 17 percent of the state was mired in the the worst category of drought, characterized as “exceptional” by the Drought Monitor scientists.

The overall drought peaked in late August, when 19 percent of the state was in the worst possible drought. It finally broke for much of the state by mid-September, and with all of the frontal storminess we’ve had during the past week this is what the state looks like now:

U.S. Drought Monitor

Now just 0.9 percent of the state is in an exceptional drought, and just 26 percent is under any sort of dry conditions.

So how bad was it this summer? I asked a state climatologist, who blogs at Atmo.Sphere. He replied:

For Texas as a whole, the drought was the worst since 2006 (big deal). Eight of Texas’ 10 climate divisions had lower Palmer Drought Severity Index (PDSI) values in 2006 than in 2008 or 2009. But for South-Central Texas (climate division 7) it was the worst since 1956, and for Southern Texas (climate division 9) it was the worst since 1953. Our previous assessment is still valid, that three counties in Central Texas and six in South Texas experienced their worst drought in the history of climate record-keeping. Our report (see .pdf file) has more details.

Now for the wow factor:

The drought was unusual because it affected a relatively small area, but was particularly intense within that area. The preliminary numbers for the PDSI for South-Central Texas have its minimum value at -6.51 (August 2009). This is only the second time since 1895 (if we trust the data) that the PDSI has dropped below -6.5 in ANY climate division in Texas. The other time was 1956, when it was below -6.5 for two months in North-Central Texas (climate division 3) and one month in South-Central Texas.

So, in terms of local intensity, it was the second most severe drought on record.

The drought had significant economic consequences. Estimated agricultural losses from Texas AgriLife Extension were $3.5 billion earlier this year, and the final numbers will probably lie in the $4 billion to $5 billion range.